I did some hacking around (with suggestions from the inimitable pabw), and started my kernel computation again. Last time, it ran for 9 days and failed when the power died. The ETA was around 38 days. This time.... 43 hours. Who now has the complete kernel matrix for 17 gigs of fMRI data? *Incrementally cached*? That'd be me. Bow, all ye data-matrix less peons.

Well, we have to use this dataset because the guys who are interested in it are giving us a ton of cash, but the purpose is to test different types of classifiers against each other (in this case, un-scaled support vector machines against an in-house dimensionality reducer under a Bayes net)